Appearing from within the Matrix, the Master reveals that the Doctor's
trial is part of a conspiracy by the corrupt High Council, who ravaged
the Earth and renamed it Ravolox to hide the theft of Matrix secrets.
Furthermore, the Valeyard is actually the distillation of the Doctor's
evil side between his twelfth and final regeneration. Brought to the
trial by the Master, Mel helps the Doctor pursue the Valeyard into the
Matrix, where they discover that he is plotting to destroy the High
Council. However, the Master has also summoned Glitz as part of his own
bid for power.

Production

In mid-1985, Doctor Who producer John Nathan-Turner and script
editor Eric Saward decided that the fourteen episodes of Season
Twenty-Three would be tied together by the umbrella theme of the Doctor
being put on trial by the Time Lords. The other principal architect of
this concept was writer Robert Holmes. At an early stage, it was hoped
that Holmes would write the first four-part segment, and then the season's
final six installments. However, Holmes indicated that while he did not
mind writing the introductory adventure, he was otherwise interested only
in the last two episodes of the season, which would tie up the running
plotline.

Having completed the first four episodes of Season Twenty-Three under the
title “The Mysterious Planet”, Holmes was commissioned to
write the concluding two-part serial, “Time Inc”, on
February 4th, 1986. On the 24th, however, BBC Head of Series and Serials
Jonathan Powell wrote to the Doctor Who production office with a
detailed and highly negative critique of “The Mysterious
Planet”. Holmes, who was in ill health as he battled hepatitis B,
was greatly demoralised by Powell's comments, and was frustrated that
he now had to put “Time Inc” on hold while he revised
“The Mysterious Planet”.

Due to Robert Holmes' ill health, Eric Saward took over
the serial from the point where the Doctor enters the Matrix

Consequently, it was not until March that Holmes was able to begin work
on his script for the first episode, now retitled “The Fantasy
Factory”. Progress then became even slower as Holmes' health
deteriorated; Saward found himself playing an ever greater role in the
writing process, effectively taking over the serial from the point where
the Doctor enters the Matrix. He deviated from Holmes' original idea
which, although still set in a Victorian environment, involved the
Doctor encountering the Duke of Clarence, who accuses him of being
Jack the Ripper and tries to drown him at the episode's cliffhanger. The
title “The Fantasy Factory” was also dropped at this point.
While this was happening, Saward and Nathan-Turner were not getting
along, and the script editor was increasingly working from home rather
than venturing into the Doctor Who production office.

On April 1st, Anthony Ainley was contracted to play the Master in the
final two episodes of Season Twenty-Three. Holmes had envisaged him as
the Doctor's chief opponent within the Matrix, but Saward tailored the
storyline to place the emphasis more firmly on the Valeyard's
machinations. Since it had been decided that the season's final six
episodes would be made together as Serial 7C, some documentation now
began to refer to the trial's last segment as “The Ultimate
Foe” parts five and six, using the working title which Pip and
Jane Baker had devised for the serial which would precede Holmes'. The
matter of titles became moot shortly thereafter, when Nathan-Turner
opted to broadcast the entire season as The Trial Of A Time Lord.
Holmes and Saward's scripts would therefore serve as parts thirteen and
fourteen of this marathon adventure. On April 13th, Saward resigned from
Doctor Who, but agreed to complete the season finale all the
same.

In Holmes and Saward's conception, the season's penultimate episode
revealed that the Valeyard was in fact the Doctor's final incarnation.
The finale then opened with the Master saving the Doctor from the
quicksand while the Valeyard kidnapped Glitz. The Doctor encountered
Popplewick again, who led him into a trap baited with an illusory Mel.
Popplewick, too, was revealed as a construct of “JJ
Chambers” -- who, in turn, was unmasked as the Valeyard. While
news reached the courtroom of the High Council's mass resignation, the
Master warned that the Valeyard had materialised his TARDIS around a
time vent in the Matrix. If the vent were to be opened for too long,
there would be catastrophic ramifications for the space-time continuum.
The Valeyard -- shown to be a pitiable old man afraid of dying --
planned to use this threat to force the Time Lords to grant him the
Doctor's remaining regenerations. The Master revealed that he was hired
by the High Council to murder the Doctor in exchange for a pardon, but
had now decided not to follow through. The Doctor bluffed his way into
the Valeyard's TARDIS just as the Valeyard opened the time vent door.
Struggling, the Doctor and the Valeyard plunged into the time vent while
the Master had Glitz seal the door, saving the universe but trapping the
Doctor for all eternity.

The original ending was inspired by the apparent deaths of
Sherlock Holmes and Professor Moriarty at the Reichenbach Falls

Sadly, Holmes was soon admitted to hospital, where he lapsed into a coma
and passed away on May 24th. Doctor Who had lost the man who was,
to that point, arguably its most successful writer. Saward was
devastated by the news, but was determined to complete the work that
Holmes had started. Unfortunately, Nathan-Turner was now having
misgivings about the downbeat ending, which had been inspired by the
1893 short story The Final Problem, in which Arthur Conan Doyle
attempted to kill off both Sherlock Holmes and his arch-nemesis
Professor Moriarty in a fall over the Reichenbach Falls. Nathan-Turner
was concerned that this would provide the BBC with a tailor-made
scenario to cancel Doctor Who, and that the viewers who followed
the season for fourteen weeks were owed a genuine conclusion to the
story. He also disliked the notion of the Valeyard being an evil future
Doctor, since this could be seen as “wasting” one of the
Doctor's lives. And Nathan-Turner now wanted to reveal that Peri, who
was seemingly killed off at the end of The Trial Of
A Time Lord (Segment Two), was alive after all.

Nathan-Turner and Saward met to try to find a way to amend the season
finale in a manner which would assuage the producer's objections, while
still respecting Holmes' original vision. These efforts were
unsuccessful, and Saward became concerned that Nathan-Turner would go
ahead and alter the scripts as he saw fit. As such, on June 4th, Saward
withdrew his permission for Doctor Who to use his version of The
Trial Of a Time Lord part fourteen. He also asked that the programme
not use the portion of part thirteen which he had written, but the BBC
refused on the grounds that this work had been performed in Saward's
capacity as a staff script editor. As such, the penultimate episode of
The Trial Of A Time Lord would be the last on which Saward was
credited. He returned to his career as a freelance writer, with his
later work including drama scripts for German radio. He also wrote
linking narration for some of BBC Audio's releases of missing Doctor
Who episodes, and contributed to the short story anthology Doctor
Who: Short Trips: Paste Tense, published by Big Finish Productions
in April 2004.

Pip and Jane Baker could not be told any of the contents
of Eric Saward's script for episode fourteen

Meanwhile, with the locations for the final two episodes of Season
Twenty-Three already scouted, and rehearsals set to begin in less than two
weeks, Nathan-Turner had to act quickly. He turned to Pip and Jane Baker.
The husband-and-wife writing team had written The
Trial Of A Time Lord (Segment Three) at very short notice, and
were familiar with the season's story arc. Immediately after receiving
Saward's notification, Nathan-Turner despatched the script for episode
thirteen to them via taxi. The next morning, he met with the Bakers at
the Doctor Who production office. Joining them was a legal
representative, who was responsible for ensuring that Nathan-Turner did
not divulge any of the contents of Saward's script for part fourteen.
This meant that the Bakers had to come up with their own way of tying
together all the season's loose ends, without any knowledge of the
original plan.

The new season finale was commissioned on June 6th. The Bakers delivered
their version of the storyline three days later, followed within the
week by the completed script. Nathan-Turner acted as the script editor;
he also made some changes to the preceding episode, such as the
description of the Valeyard as being an amalgamation of the Doctor's
evil impulses from his own future, rather than his final incarnation.
The time vent was replaced by the particle disseminator, and instead of
the Valeyard being a weak man masquerading as JJ Chambers, he was now a
much stronger figure masquerading as Mr Popplewick. The Master played a
more overtly villainous role, as opposed to the almost antiheroic
portrayal planned by Holmes and Saward, while the role of the Keeper of
the Matrix was significantly reduced (much to the disappointment of
actor James Bree).

The new scripts were quickly delivered to Chris Clough, who would be
directing the entirety of Serial 7C. A week later, location filming for
the two-part finale began with the scenes on the beach at Camber Sands in
Camber, East Sussex on June 23rd and 24th. Unfortunately, the beach hut
which Clough's team had arranged to use as the Master's TARDIS was found
to be locked, forcing the crew to seek the permission of the Harbour
Authority to break in. It was later learned that the hut was no longer
the property of the Authority -- provoking an unhappy response from the
actual owner, and a hasty apology from the BBC!

June 30th marked a nervous Bonnie Langford's first work on
Doctor Who as the new companion, Mel

Then, from June 30th to July 3rd, Gladstone Pottery Museum in Longton,
Staffordshire provided the Victorian simulacrum where the Fantasy Factory
was located. This marked a nervous Bonnie Langford's first work on
Doctor Who as the new companion, Mel. Production then concluded
with a two-day block in BBC Television Centre Studio 1. Wednesday, July
16th concentrated on material in the Master's TARDIS, while Thursday,
July 17th saw the use of the courtroom set for the last time. Part of
the Bakers' aim in writing episode fourteen was to incorporate its
destruction, since they had loathed writing the trial scenes for The Trial Of A Time Lord (Segment Three).
This was not the end of Doctor Who's twenty-third production
block, however: the majority of parts nine through twelve would be
recorded during the following weeks.

The conclusion of work on The Trial Of A Time Lord brought the
season-long involvement of Lynda Bellingham and Michael Jayston to an
end. Bellingham went on to play recurring roles in All Creatures
Great And Small, At Home With The Braithwaites and The
Bill, as well as appearing as a panellist on Loose Women. She
was awarded an OBE in 2014 in recognition of her volunteer work, but
sadly passed away on October 19th of that year after a battle with
colorectal cancer. Jayston continued to amass a number of television
credits, including A Bit Of A Do, Cluedo, Outside
Edge and Emmerdale.

In post-production, it quickly became clear that there was no way to
edit part fourteen down to the required twenty-five minutes without the
narrative becoming totally incomprehensible. Instead, Nathan-Turner
asked Jonathan Powell to allocate the episode a thirty-minute timeslot.
Powell and the BBC brass approved of the way Season Twenty-Three was
shaping up, and so the request was granted. This satisfaction was also
manifested in the announcement on August 19th that Doctor Who
would be returning for its twenty-fourth season.

However, any sense of euphoria was muted when the early episodes of The
Trial Of A Time Lord debuted to weak ratings -- the long break between
seasons and potent opposition from American action import The
A-Team taking audience levels below the already disappointing
viewing figures of Season Twenty-Two (although the Appreciation Index
generally improved). And then, on October 29th, any euphoria was
silenced altogether when Nathan-Turner was compelled by Powell and BBC1
Controller Michael Grade to inform Colin Baker that he was being
replaced as the star of Doctor Who.

John Nathan-Turner was furious when he was told that he
was being kept on Doctor Who for Season
Twenty-Four after all

In return for being this bearer of bad news, Nathan-Turner was assured by
Powell and Grade that he would be allowed to move on from Doctor
Who at the end of November. As such, Nathan-Turner was furious when he
was told by Powell on November 28th that he was being kept on the
programme for Season Twenty-Four after all. So it was that, as The
Trial Of A Time Lord adjourned itself from television screens on
December 6th and the news of Baker's firing was reported by the press on
December 13th, the producer found himself trying to reach a compromise
with Baker and the BBC.

Nathan-Turner convinced his superiors to offer Baker a contract for a
final four-part adventure, which would climax with the Doctor regenerating
into his seventh incarnation. Baker's counter-proposal was that he be
permitted one additional full season in the lead role; otherwise, he
feared that his continued attachment to Doctor Who would result
in him missing out on too much work over the coming nine months. When
the BBC refused, Baker walked away. On December 18th, the BBC confirmed
that the actor would not be returning to Doctor Who. Then, any
hope of mending fences was lost when an interview with the actor was
published in the Sun on January 6th, 1987. Here Baker expressed
regret at his dismissal from Doctor Who, and spoke scathingly of
Grade and the cowardly way he felt the Controller had dealt with
him.

Baker would go on to a long career in theatre, and continued to make
appearances on television including episodes of Jonathan Creek,
Casualty, Doctors and Hustle. And despite the
acrimonious circumstances of his departure, Baker would maintain close
ties with Doctor Who. In 1988, he replaced Jon Pertwee in the stage
play Doctor Who: The Ultimate Adventure, and returned to television
for the thirtieth-anniversary special Dimensions In
Time in 1993. He also played the Doctor-like title character in
the direct-to-video series The Stranger for BBV throughout the
Nineties, and appeared as himself in the fiftieth-anniversary spoof
The Five(ish) Doctors: Reboot. Most significantly, in 1999, Baker
returned to the role of the Sixth Doctor for Big Finish Productions, and
helped to rehabilitate the character over the course of dozens of audio
plays in the years that followed.